1. Field of the Invention
This invention relates to a glass run of an automobile for sliding and guiding the peripheral edge of a moving window glass of a door, and for sealing between the window glass and the door when the window glass is fully closed.
2. Description of Related Art
A conventional glass run channel (glass run) 80 of an automobile is shown in FIG. 7 for sliding and guiding the peripheral edge of a moving glass (door glass) 10 upwardly and downwardly. Such a glass run is disclosed in the Related Art Section of Japanese Utility Model Application Laid-Open No. 5-62312. The glass run 80 comprises a main body 81 and two seal lips 82, 83. The main body 81 has a generally U-shaped cross section and is set in a holder (door sash) 20. The seal lips 82, 83 project from both opening ends of the main body 81 toward the bottom surface of the main body 81. The seal lips 82, 83 are provided with notches 86 at their roots, respectively, so as to decrease the load of the door glass 10 moving, which bears against the seal lips 82, 83 when the door glass 10 slidably moves. With the thus-provided notch 86, however, each seal lip 82, 83 is liable to be bent on the boundary of notch 86, which deteriorates the sealing and gripping properties of the glass run 80 compared with another conventional glass run (not shown) without any notches. Such defects of the glass run 80 are pointed out in the Specification of the above-mentioned No. 5-62312.
On the other hand, FIG. 8 shows another glass run 30, which is disclosed in the Embodiment Section of the same Specification. The glass run 30 comprises a main body 31 and two seal lips 32, 33. The main body 31 has a generally U-shaped cross section and is set in the holder 20. The seal lips 32, 33 project from both opening ends of the main body 31 toward the bottom surface of the main body 31. At least one of two seal lips, e.g., the seal lip 32 in FIG. 8, is thinned in its wall thickness compared with that of other conventional glass run, and is provided with a sponge rubber layer 34 attached to the back side thereof.
According to the Specification of the above-mentioned No. 5-62312, the glass run 30 with the thinner lip 32 and the sponge rubber layer 34 shows an increased flexibility and decreased load of the slidably moving door glass 10, which facilitates the vertical movement of the door glass 10. Furthermore, the seal lip 32 bends over its full length and is not bent at its root, so the sealing and gripping properties are secured for the glass run 30 as well as a conventional glass run, so the door glass 10 never rattles, the Specification describes.
However, when the seal lip 32 is thinned in its wall thickness and the sponge rubber layer 34 is attached to the back side of the seal lip 32, so that when the seal lip 32 bends over its full length and is not bent at its root, as is the case with the glass run 30 shown in FIG. 8, the following problem occurs. Namely, when the door glass 10 vertically moves, and the contact position on the door glass, where the door glass 10 slidably contacts the seal lip 32, varies in the direction of the inside and outside of an automobile, as shown in FIG. 9, the radius of curvature on the outer surface of the seal lip 32 easily varies over its full length. Therefore, the contact width W of the seal lip 32 and the door glass 10 varies to vary their contact area, which causes the adverse effect for slidable movement of the door glass 10. By the way, it is also disclosed in the same Specification that the sponge rubber layer 34 is divided at a position near its root to form a branch. The tip of the branch is connected to the middle portion on the inner surface of a side wall of the main body to form a hollow portion. Even if the hollow portion is formed, there is no change in that the above-mentioned problem remains.
It is an object of this invention to provide a glass run of an automobile which can achieve the following effects (1) to (4).
(1) A seal lip is thickened in its wall thickness at its middle portion in a manner that the back side of the seal lip projects more to the other side at the middle portion than at its root portion, thereby forming a convex at the middle portion on the back side of the seal lip. Accordingly, when a door glass moves, and a contact position on the door glass, where the door glass slidably contacts the seal lip, varies, the radius of curvature on the outer surface of the seal lip hardly varies over its full length except for the root portion of the seal lip. Therefore, the contact width of the seal lip and the door glass, consequently, their contact area, hardly varies, which never causes adverse effect for slidable movement of the door glass.
(2) when the door glass moves, and the contact position on the door glass, where the door glass slidably contacts a seal lip, varies, the seal lip easily bends by its root because of the concave formed in the root portion on the back side of the seal lip. Moreover, the elasticity of the seal lip is reinforced by a sponge elasticity-reinforcing member. As a result, the door glass is prevented from rattling without increasing the force in controlling the movement of the door glass.
(3) When a door is strongly closed with the door glass being slightly opened, the door glass swings widely. Even if the door glass swings widely, the seal lip is prevented from contacting a side wall of a channel portion by the sponge elasticity-reinforcing member intervening therebetween, which prevents generation of a contacting sound.
(4) With the sponge elasticity-reinforcing-member, occurrence of permanent set in fatigue or abnormal deformation of the seal lip is prevented, and the follow-up quality of the seal lip to the door glass and the sealing quality of the seal lip are not deteriorated.
A first invention resides in a glass run comprising a channel portion including a bottom portion and inner and outer side walls. The inner side wall is provided inside of an automobile, while the outer side wall is provided outside of the automobile. The glass run further comprises inner and outer seal lips projecting into the channel portion from the inner and outer side walls respectively. The inner seal lip is provided inside of the automobile, while the outer seal lip is provided outside of the automobile. The seal lips have back sides facing inside of the channel portion. At least the inner seal lip is thickened in its wall thickness at its middle portion in a manner that the back side of the seal lip projects more inwardly into the channel portion at the middle portion than at a root portion of the seal lip, thereby forming a convex at the middle portion on the back side of the seal lip while relatively forming a concave at the root portion on the back side of the seal lip. The glass run further comprises a sponge elasticity-reinforcing member provided between the root portion on the back side of the inner seal lip and the inner side wall.
The sponge elasticity-reinforcing member may extend to the middle portion of the seal lip. In such a case, it is preferable that the wall thickness of sponge on the middle portion is thinner than that formed between the root portion and the inner side wall.
A second invention resides in a glass run comprising a channel portion including a bottom portion and inner and outer side walls. The inner side wall is provided inside of an automobile, while the outer side wall is provided outside of the automobile. The glass run further comprises inner and outer seal lips projecting into the channel portion from the inner and outer side walls respectively. The inner seal lip is provided inside of the automobile, while the outer seal lip is provided outside of the automobile. The seal lips have back sides facing inside of the channel portion. At least the inner seal lip is thickened in its wall thickness at its middle portion in a manner that the back side of the seal lip projects more inwardly into the channel portion at the middle portion than at a root portion of the seal lip, thereby forming a convex at the middle portion on the back side of the seal lip while relatively forming a concave at the root portion on the back side of the seal lip. The glass run further comprises a sponge elasticity-reinforcing member formed like a bridge for connecting the middle portion on the back side of the inner seal lip and the inner side wall.
In the first or second invention, the channel portion is preferably formed by extrusion molding from a solid rubber or a solid thermoplastic elastomer (hereinafter referred to as TPE) having a spring hardness of Hs 70xc2x0 to 90xc2x0 in accordance with JIS A. When priority is given to the permanent set resistant property of the seal lips of the glass run, the seal lips are formed from a solid ethylene-propylene-diene terpolymer (EPDM) rubber. In this case, it is preferable that the channel portion is formed from the same solid rubber as the seal lips. A solid EPDM rubber having a spring hardness of Hs 70xc2x0 to 80xc2x0 in accordance with JIS A is more preferable.
The seal lips are preferably formed from a solid rubber or a solid TPE having a spring hardness of Hs 50xc2x0 to 90xc2x0 in accordance with JIS A and being different from a solid rubber or a solid TPE which forms the channel portion in compounding ratio of materials. A solid EPDM rubber having a spring hardness of about Hs 70xc2x0 is preferable from a viewpoint of permanent set in fatigue resistant property. The seal lips are preferably formed from the same kind of material as is used for the channel portion from a viewpoint of successive integral forming.
The sponge elasticity-reinforcing member is preferably formed from a sponge rubber or a sponge TPE. A TPE foam (sponge), especially an olefin-based TPE (TPO) foam, or a sponge EPDM rubber is preferable. When the seal lips are formed from a solid EPDM rubber and the sponge elasticity-reinforcing member is formed from a sponge EPDM rubber, the bonding connection between connecting surfaces of these two components are strengthened. Because both are the same kind of materials and the SP (Solubility Parameter) of these components are the same or closer to each other.
When the seal lips and channel portion are formed from a solid TPO, a material for the sponge elasticity-reinforcing member is preferably decided as follows. Namely, if the object of the material selection for the seal lips and channel portion is to eliminate the vulcanization process and simplify the manufacturing process to thereby decrease the manufacturing cost, the sponge elasticity-reinforcing member is preferably formed from a sponge TPO. On the other hand, if the object is to make up for the decrease in the flexibility of the seal lips, the sponge elasticity-reinforcing member is preferably formed from a sponge EPDM rubber. In this case, the sponge elasticity-reinforcing member can be formed by simultaneous extrusion molding by inserting a previously prepared linear sponge EPDM rubber.
It is preferable that the surface of the bottom portion is covered with a low-friction layer. The low-friction layer can be formed by conventional techniques such as applying a urethane coating or bonding a polyethylene sheet. The low-friction layer on the bottom portion is preferably formed from a TPE or a resin having a Shore D type hardness of 45xc2x0 to 60xc2x0. It is more preferable that the low-friction layer is formed from a TPO having a Shore D type hardness of about 55xc2x0. The low-friction layer is preferably formed by simultaneous extrusion molding from a TPO.
Further objects of this invention will become evident upon an understanding of the illustrative embodiments described below. Various advantages not specifically referred to herein but within the scope of the instant invention will occur to one skilled in the art upon practice of the presently disclosed invention. The following examples and embodiments are illustrative and not seen to limit the scope of the invention.